Use a flashlight?
If you want to be able to recover from a job that loses power part way through, then you need to reliably start over from the exact same spot on the second run. This pretty much requires homing switches. Each time you turn on the machine, you should perform a homing cycle. This will put the machine in a known location. When you prepare to start your job, you need to zero your tool. You should also write down the machine coordinates of your Zero position, just in case you can’t return there automatically after the power outage (though the Zero position is supposed to be stored in flash and persist across power cycles).